The present invention relates to a device for protection in the case of a drop of the voltage of a d.c. power supply which includes a capacitor in parallel with its terminals, said device having first and second supply voltage inputs and two outputs between which a circuit to be powered may be included.
As is known, domestic electrical appliances more and more utilize control devices with memory functions, in conjunction with timers, which put the appliance into operation after a predetermined time interval.
In the event of a current failure during said interval the information is generally seriously disturbed. It has already been attempted to mitigate the effects of brief current failures by connecting a capacitor in parallel with the input, which capacitor may at the same time constitute a smoothing capacitor. This capacitor discharges into the circuit and furnishes the required voltage and current for some time.
Circuit arrangements comprising such capacitors are given in all manuals and for example in the "Cours de base de l'agent technique electronicien" by C. Granfils, published by Les Editions Chiron.
Obviously the users of such an appliance wish that in the event of a failure said appliance keeps operating correctly for the longest possible time.
The present invention provides a solution to these problems; it is based on the recognition that an integrated circuit can correctly preserve the information it has received, even if it loses its dynamic properties, in the event of a reduced current.